dumb question, sort of related to why trout are cold water fish

[k-bob]

Trout are cold water fish because cold water holds more oxygen right? So when streams warm up - as in the crazy heat we had this year - the trout will head for colder tribs or cool seeps into streams, or they might hang around under a waterfall.

here's the dumb question: is there some reason that cold liquids hold more gas? For example, cold soda has more bubbles? can we change this? just kidding about that...

another question: since trout are cold blooded, is water temp above 68 or whatever a problem for the fish to maintain body temps? is that another water temp issue beyond the oxygen content issue?

thanks, and I am hoping for answers from Scientists

 

[Pontus]

According to Henry's Law the solubility of a gas in water is inversely proportional to the water's temperature, assuming constant pressure. You can think of it this way. When the temperature increases, particles are moving at a higher rate, causing more gases to escape. When it's colder, the gases are moving much slower and are therefore less likely to leave the water.

 

[k-bob]

"When the temperature increases, particles are moving at a higher rate, causing more gases to escape."

thanks, makes sense.

anyone know this part:

"since trout are cold blooded, is water temp above 68 or whatever a problem for trout body temps?" I assume they can't sweat!

 

[goodfortune]

I'll try to answer this one...

Since trout are cold blooded creatures, their internal tissues and organs will be at the same temperature as the water in which they live. In turn, warmer tissues and organs will mean higher levels metabolism, and more oxygen will be needed to support higher levels of metabolic activity.

Also, trout cannot utilize dissolved oxygen (DO) as efficiently as many other fish, such as bass, so they need to live in waters that are high in DO, like the cold, aerated water in trout streams.

Considering that warmer water holds less oxygen than colder water, there comes a point where trout cannot gain enough dissolved oxygen from the water to support higher levels of metabolism at warmer water temps. In trout, this seems to occur when water temps rise into the low to mid 70's.

Add-on: I also will not fish water that is warmer than 68F; to a trout, 70F is like 110+ F to us.

Hope that helps

 

[k-bob]

"Considering that warmer water holds less oxygen than colder water, there comes a point where trout cannot gain enough dissolved oxygen from the water to support higher levels of metabolism at warmer water temps."

Ok, so warmer water has less oxygen, and trout in it need more oxygen, thanks! Will keep watching those water temps.

 

[wsender]

I believe as water warms it becomes less dense as well. This means that even if Henry's Law didn't exist and the levels of dissolved gases were constant at all temperatures trout would have to push more water through they're gills in-order to absorb the same amount of oxygen. Think of this like altitude change for humans.

 

[pszy22]

Trout really get double dipped when the water heats up. Since they are cold blooded, as the water heats up, so do they, meaning their metabolism increases. As their metabolism increases, they need more oxygen, and of course, we know there is less oxygen available.

In effect, they spend alot of time gasping for air.

 

[wetnet]

if you understand oxygen levels and temps you are most suited to find your quarry. Trout are not as smart as you think, they need oxygen so depending on the temps and oxygen levels they move to areas where Oxygen content is high and there is a food source. there are lots of things that deplete oxygen, bacteria is a biggie. They are the biggest friends and foe of fish. They clean up the water by breaking down nutrients...Fecal matter decaying plants etc. They come first and die first. When bacteria get loads of nutrients from pollution they multiple, they also like a non cleaned aquarium in huge numbers they use all of the available oxygen and can deplete the streams of enough oxygen that you have a fish kill. Lots of factors are part of the oxygen levels, temps are a big one no matter what. Bacteria thrive and multiple faster in higher temps.